【发布时间】：2020-09-17 00:24:18
【问题描述】：
我已经制作了一个工作查找的写入标签应用程序，我将数据文本存储到 NFC 标签中的标记事物（例如：计算机 1）。写入和读取都可以正常工作。但是当我阅读我知道具有唯一十六进制 ID 的信息文本时，我需要阅读每个标签具有的十六进制 ID（因为我在使用 google play 应用程序测试它时看到了那个）。但我不知道该怎么做。我真的不擅长编码，所以请帮助我。
代码如下：
public class MainActivity extends Activity {
NfcAdapter mAdapter;
Tag mTag;
PendingIntent mPI;
IntentFilter mFilter[];
String userData,yo;
boolean writeMode;
Context context;
TextView tvNFCContent, Timer,Low;
Button start, pause, reset, lap ;
long MillisecondTime, StartTime, TimeBuff, UpdateTime = 0L ;
Handler handler;
int Seconds, Minutes, MilliSeconds ;
ListView listView ;
String[] ListElements = new String[] { };
List<String> ListElementsArrayList ;
ArrayAdapter<String> adapter ;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
tvNFCContent = (TextView) findViewById(R.id.data);
Timer = (TextView)findViewById(R.id.timer);
tvNFCContent.addTextChangedListener(watch);
handler = new Handler() ;
mAdapter = NfcAdapter.getDefaultAdapter(this);
mPI = PendingIntent.getActivity(getApplicationContext(), 0,
new Intent(this,getClass()).addFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP),0 );
IntentFilter tagDetected = new IntentFilter(NfcAdapter.ACTION_TAG_DISCOVERED);
IntentFilter filter2 = new IntentFilter(NfcAdapter.ACTION_NDEF_DISCOVERED);
mFilter = new IntentFilter[]{tagDetected,filter2};
mAdapter = NfcAdapter.getDefaultAdapter(this);
if (mAdapter == null) {
// Stop here, we definitely need NFC
Toast.makeText(this, "This device doesn't support NFC.", Toast.LENGTH_LONG).show();
finish();
}
readFromIntent(getIntent());
}
private void readFromIntent(Intent intent) {
String action = intent.getAction();
if (NfcAdapter.ACTION_TAG_DISCOVERED.equals(action)
|| NfcAdapter.ACTION_TECH_DISCOVERED.equals(action)
|| NfcAdapter.ACTION_NDEF_DISCOVERED.equals(action))
{
Parcelable[] rawMsgs = intent.getParcelableArrayExtra(NfcAdapter.EXTRA_NDEF_MESSAGES);
NdefMessage[] msgs = null;
if (rawMsgs != null) {
msgs = new NdefMessage[rawMsgs.length];
for (int i = 0; i < rawMsgs.length; i++) {
msgs[i] = (NdefMessage) rawMsgs[i];
}
}
buildTagViews(msgs);
}
}
private void buildTagViews(NdefMessage[] msgs) {
if (msgs == null || msgs.length == 0) return;
String text = "";
// String tagId = new String(msgs[0].getRecords()[0].getType());
byte[] payload = msgs[0].getRecords()[0].getPayload();
String textEncoding = ((payload[0] & 128) == 0) ? "UTF-8" : "UTF-16"; // Get the Text Encoding
int languageCodeLength = payload[0] & 0063; // Get the Language Code, e.g. "en"
// String languageCode = new String(payload, 1, languageCodeLength, "US-ASCII");
try {
text = new String(payload, languageCodeLength + 1, payload.length - languageCodeLength - 1, textEncoding);
} catch (UnsupportedEncodingException e) {
Log.e("UnsupportedEncoding", e.toString());
}
tvNFCContent.setText("NFC Content: " + text);
TimeBuff += MillisecondTime;
handler.removeCallbacks(runnable);
}
NdefMessage[] getNdefMessage(Intent intent)
{
NdefMessage[] msgs = null;
Parcelable[] rawMsgs = intent.getParcelableArrayExtra(NfcAdapter.EXTRA_NDEF_MESSAGES);
if(rawMsgs != null)
{
msgs = new NdefMessage[rawMsgs.length];
for(int i=0; i<rawMsgs.length; i++)
{
msgs[i] = (NdefMessage)rawMsgs[i];
}
}
return msgs;
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
@Override
protected void onNewIntent(Intent intent) {
// TODO Auto-generated method stub
setIntent(intent);
readFromIntent(intent);
if (NfcAdapter.ACTION_TAG_DISCOVERED.equals(intent.getAction())){
mTag = intent.getParcelableExtra(NfcAdapter.EXTRA_TAG);
}
super.onNewIntent(intent);
if(intent.getAction().equals(NfcAdapter.ACTION_NDEF_DISCOVERED))
{
Toast.makeText(getApplicationContext(),"Ndefdiscovered",Toast.LENGTH_SHORT).show();
}else if(intent.getAction().equals(NfcAdapter.ACTION_TAG_DISCOVERED))
{
mTag = intent.getParcelableExtra(NfcAdapter.EXTRA_TAG);
Toast.makeText(getApplicationContext(),"Smartcard detected",Toast.LENGTH_SHORT).show();
StartTime = SystemClock.uptimeMillis();
handler.postDelayed(runnable, 0);
NdefMessage[] messages = getNdefMessage(intent);
if(messages == null)
{
Toast.makeText(getApplicationContext(),"There Is No Data",Toast.LENGTH_SHORT).show();
return;
}
byte[] payload = messages[0].getRecords()[0].getPayload();
userData = new String(payload);
} else {
Toast.makeText(getApplicationContext(),"Undefined smartcard",Toast.LENGTH_SHORT).show();
}
}
public Runnable runnable = new Runnable() {
public void run() {
MillisecondTime = SystemClock.uptimeMillis() - StartTime;
UpdateTime = TimeBuff + MillisecondTime;
Seconds = (int) (UpdateTime / 1000);
Minutes = Seconds / 60;
Seconds = Seconds % 60;
MilliSeconds = (int) (UpdateTime % 1000);
Timer.setText("" + Minutes + ":"
+ String.format("%02d", Seconds) + ":"
+ String.format("%03d", MilliSeconds));
handler.postDelayed(this, 0);
}
};
@Override
protected void onPause() {
// TODO Auto-generated method stub
super.onPause();
mAdapter.disableForegroundDispatch(this);
}
@Override
protected void onResume() {
// TODO Auto-generated method stub
super.onResume();
mAdapter.enableForegroundDispatch(this, mPI, mFilter, null);
}
TextWatcher watch = new TextWatcher(){
@Override
public void afterTextChanged(Editable arg0) {
// TODO Auto-generated method stub
}
@Override
public void beforeTextChanged(CharSequence arg0, int arg1, int arg2,
int arg3) {
// TODO Auto-generated method stub
}
@Override
public void onTextChanged(CharSequence s, int a, int b, int c) {
// TODO Auto-generated method stub
}
};
}
对不起，我上传了整个代码，我只是想让任何愿意帮助我的人都能轻松完成。
【问题讨论】：